Originally Posted by CloudsMystique
I would assume she's coming down toe first, but she hasn't done it except when I'm riding her, so I haven't seen it happen from the ground.
If nothing else, such as tack, has changed, then I really would suspect something done by or irritated by the farrier. If your horse is fine without a rider, but tripping with you aboard, then I would think she is off balance.
Have your farrier back out and have him watch the horse with and without you riding. If she is in shoes, then I might ask to have them pulled to check underneath.